Diaphragm valves are generally known and include a body seal arrangement and a valve seat arrangement. The body seal typically is achieved at or near the outer peripheral area of the diaphragm by clamping and compressing the diaphragm between facing surfaces of the valve body. Imperfections in the body surf aces and diaphragm surface, however, can require very high compression of the diaphragm to achieve a satisfactory seal. Harder materials for the diaphragm exacerbate the body seal problem at the clamping surfaces.
A valve seat is used to seal off an inlet and outlet passageway by engaging with the diaphragm. Prior designs tend to have large surface areas of the seat exposed to the fluid, thus providing possible leak paths and contamination. Valve seat surfaces can be pre-formed with specific contours to improve sealing, but such steps tend to be time consuming and thus more expensive.
Accordingly, it is a general objective of the present invention to provide a diaphragm-type valve that has improved body seal and valve seat arrangements and that can be manufactured at competitive costs and performance, with higher flow rates achieved using similar overall device dimensions.